[Zope] Integrating Zope with Excel.

[Paul Winkler]

On Tue, Aug 31, 2004 at 11:47:26AM +0100, Chris Withers wrote:
> Joe Goldthwaite wrote:
> 
> >I've never understood the threading issues - too complex for my feeble
> >brain.  I know that if one user performs a large job through Zope, it stops
> >responding to other users until the big job is finished. 
> 
> That's odd, you should look into that, it's not the norm...

I've seen the same behavior in a few situations:

1) an External Method was making an http request using httplib
to a host that had become (wrongly) firewalled.
I don't know how this could completely block zope, but that
was the behavior I observed. A bit of using gcc as described
in the "Debug a Spinning Zope" article helped me identify
the ext. method in question and rewrite it so it can't
possibly block like that.

2) When using ZEO with an inadequate client cache, it is possible
to end up with zope apparently doing nothing but waiting for ZEO
while the cache thrashes.  This  happened to us when somebody
was downloading a very large file (more than twice the size of the
client cache).  A look at the event logs showed a long stream of ZEO client 
cache flip messages during the time in question.  
We drastically increased the size of the client cache and haven't had 
that problem since.
I think that in this case, zope was still servicing requests, it
was just doing so extremely slowly.  When the download finished,
everything instantly cleared right up.
 
-- 

Paul Winkler
http://www.slinkp.com